Apparatus and Method for Carrying Out Sequential Creasing and Laser Cutting on a Sheet Material

This application is related to and claims priority to European Application EP24169819 entitled “Apparatus and Method for Carrying Out Sequential Creasing and Laser Cutting on a Sheet Material” filed 11 Apr. 2024, the contents of which are hereby incorporated by reference as if set forth in their entirety.

The present invention relates to the technical field of processing sheets of a material for packaging, displays and in general carton structures such as cardboard and corrugated cardboard. More particularly, the invention relates to an apparatus for carrying out sequential creasing and laser cutting on a cardboard sheet or a paperboard sheet and similar materials, particularly corrugated cardboard and similarly rigid or stiff material, and to a related method.

Packaging, in particular cardboard boxes, is used in a wide range of product sectors, from food to entertainment, from mechanics to furnishings. In fact, packaging protects the product contained therein, facilitating its transport and preserving its integrity.

With particular reference to cardboard boxes, the process for their production involves two fundamental steps, namely cutting the desired shape of a box on a sheet of cardboard and creasing said sheet, which consists in producing one or more grooves or fold lines on the rigid (stiff) sheet of cardboard to facilitate folding of the sheet of cardboard, thereby obtaining the box of the desired shape. Creasing substantially consists in a “yielding” of the fibres of the stiff material of the cardboard, so that they can better withstand the folding operation. Creasing is generally carried out before cutting.

The same technology applies also to cardboard sheets for obtaining different products, such as cardboard displays, corrugated carton structures and the like.

The current technologies for the production of cardboard and corrugated cardboard packaging and displays (exhibitors) are mainly based on cutting and creasing processes carried out using traditional dies, both flat and rotary. These systems offer high production speeds, but they have a limitation due to the lack of flexibility associated with the use of the “die” tool. This does not allow for easily customized production, as die replacement is required for each job change, resulting in machine stops and setup times.

Dies of the known art are commonly produced by specialized external companies, leading to logistic complications and delays in the production process. Additionally, the presence of a mechanical tool limits the possibility of complex and customized processes due to direct contact during processing.

In parallel, there is a strong need for highly customized “on-demand” productions, which require the ability to adapt the dimensions of packaging and displays to specific merchandise. However, production batches are often small and do not fit well with traditional technologies that require producing a creasing or cutting dye.

The introduction of large-format digital printers, with the intrinsic possibility of extreme customization, is further driving the demand for digital cutting and creasing systems. Although traditional plotter systems equipped with mechanical tools offer this possibility, productivity remains limited compared to market demands.

To date, a cutting process by means of a laser apparatus is known for cutting sheet material in the form of cardboard or corrugated cardboard, but this laser cutting process is carried out on specialised machines or apparatus, after creasing on a different dedicated machine, with no possibility of carrying out a continuous process.

There is therefore the need to provide an “all-in-one” apparatus for performing consequential creasing and cutting, in order to overcome all the disadvantages related to low productivity, unnecessary transportation, high energy consumption, scrap optimization, production waste and so on.

An aim of the present invention is to overcome the drawbacks of the known apparatus and methods for creasing and cutting sheets of material like cardboard and similar.

In particular, an object of the invention is to provide an “all-in-one” apparatus for sequentially creasing and cutting sheets of packaging, display or corrugated carton structures material such as cardboard and the like, with no downtime between the two processes.

Another object of the invention is to provide such an apparatus provided with an automatic control of the status of work, in order to have the highest precision operation.

Still another object of the invention is to provide “on demand” production, with fully digitalized processing, such that every sheet can be processed according to different specifications according to the actual demand, or requirements of the final product, such as the cutting pattern, length and shape.

A further object of the invention is to provide a related method for sequentially creasing and cutting sheets of packaging, display or corrugated carton structures material such as cardboard and the like.

These and other objects are achieved by the apparatus of the invention as claimed and by a related claimed method. The invention also relates to a computer program for performing the claimed method using the claimed apparatus.

Advantageous embodiments of the invention are disclosed in the dependent claims.

Substantially, the invention relates to an apparatus for creasing and cutting sheets of packaging, display or corrugated carton structure material such as cardboard and the like, comprising: an optical station provided with a conveyor belt () apt to receive a sheet to be processed and to feed it along the optical station, the optical station also comprising an optical register designed to acquire parameters of the received sheet such as thickness of the sheet, creasing pattern, laser cutting pattern, X/Y offset positions, rotation angle, print deformations, and the like; a creasing module provided downstream of the optical station for carrying out creasing on the sheet, the creasing module being provided with a creasing controller receiving the parameters acquired at the optical station and a creasing conveyor belt apt to receive the sheet from the optical station conveyor belt and to feed it along the creasing module; a laser cutting module provided downstream of the creasing module for carrying out sequential laser cutting on the sheet exiting from the creasing module, the laser cutting module being provided with a laser cutting controller receiving the parameters acquired at the optical station and a laser cutting conveyor belt apt to receive the sheet from the creasing module and feed it along the creasing module; a programmable logic controller (PLC) controlling the operations of the optical station, creasing module and cutting module; and, a processing unit operatively connected to the PLC controller.

The processing unit receives as input a set of data including parameters related to creasing and cutting operations and the values of speed of the optical station conveyor belt, the creasing conveyor belt and the cutting conveyor belt, wherein said processing unit processes the input data and carries out a real-time control on the optical station conveyor belt, creasing conveyor belt and cutting conveyor belt speeds as a function of the parameters of creasing and laser cutting operations both at the creasing module and at the laser cutting module, in order to control the speeds of the conveyor belts and in one embodiment, to synchronize the conveyors at the same speed because the conveyor belt speeds adapt to the parameters related to least the creasing and cutting operations, to optimize productivity.

Further features of the invention will appear clearer from the following detailed description and drawings.

With reference to the figures, an apparatus for sequential and/or simultaneous execution of creasing and cutting on sheets of paper, cardboard and similar will now be described in more detail.

is a three-dimensional rendering representation of such apparatus, globally referenced by number, in which the main modules constituting it are shown, whileis a schematic representation. Key components of the apparatusare the creasing moduleand the laser cutting module, that, placed in close sequence, enable the pursued benefits to be achieved by the subject invention.

Advantageously, a feeder moduleis provided to pick up sheets S, S, . . . , Sn from a stack of sheetsand load them individually to the creasing module. Similarly, a stacker moduleis provided to collect in a stackthe processed sheets coming out from the laser cutting module.

It should be noted that the apparatusworks seamlessly: the feeder modulecontinuously supplies sheets S, S, . . . , Sn to the creasing moduleand the stacker modulecontinuously collects the treated sheets into a sheet stack.

In a conventional way, the creasing moduleis intended to receive a plurality of sheets to be processed and to carry out creasing according to pre-loaded instructions. For this purpose, the creasing module is operatively connected to a programmable logic controller (PLC), that controls its operation. A specific apparatus Job Controller, in communication with the PLC, can also be provided for sending instructions to the creasing and laser cutting modules, e,g, creasing instructions to the creasing module and laser cutting instructions to the laser cutting module. The features of such creasing module are known per se in the art and to the skilled person and advantageously include an overhead creasing mechanism that creases the sheets S, S, . . . Sn from above as the sheets S, S, . . . Sn lie essentially flat as they travel along on the conveyor belt. The creasing mechanism may include a plotter capable of movement along two orthogonal axes, and a wheel or other rolling member that applies pressure to the sheet to form creases in the sheet, typically one or more grooves or fold lines on the rigid (stiff) sheet of cardboard to facilitate folding of the sheet of cardboard. The plotter may advantageously provide the wheel or other rolling member motion along a plane.

The motion of the plotter along the two axes is preferably controlled by respective axis motors. In one embodiment there is one pressure creasing device mounted on a support movable along one bar located transverse to the length of the module (with respect to the machine direction). The bar is mounted slidably on guides provided at the side of the creasing module so that the bar can in turn be moved with the creasing device, longitudinally along the creasing module.

In other embodiments, other mechanical and other devices suitable for providing creases on a sheet, may be used and other modes of translational movement may also be used.

In a standard way, in fact, the creasing modulehas a conveyor beltconfigured to receive the sheets S, S, . . . , Sn to be creased. The conveyor beltmoves the sheets through module, where creasing takes place. As they exit creasing module, the sheets on conveyor beltare fed to the laser modulefor cutting operations.

The laser cutting modulemay also be a machine conventionally known per se in the industry. Laser cutting modulemay advantageously include an overhead laser device adapted to direct a laser downward toward the sheets S, S, . . . Sn as the sheets S, S, . . . Sn lie essentially flat as they travel along on the conveyor belt. The laser device is moveable by means of a plotter capable of movement along two orthogonal axes and in one embodiment there are provided two bars that are moved by means of four linear motors, i.e. one motor is located at each extremity of a same axis. In one embodiment, there is one laser device mounted on a support located at the intersection of said two bars.

In one advantageous embodiment laser moduleincludes a laser device mounted on a plottercapable of movement along two orthogonal axes and creasing moduleincludes a creasing device mounted on a plottercapable of movement along two orthogonal axes. The creasing device may include a rolling member suitable to apply pressure to the sheet present in the creasing module. The combination of creasing and cutting stations both using a plotter results in the advantage of total flexibility and high production speeds. The time required to change from production of one product to another is in fact very reduced.

Other modes of translational movement may be used in other embodiments.

In a one embodiment the laser cutting module has a working support for laser cutting and/or marking operation, comprising

The cutting or working support is object of a co-pending application in the name of the present Applicant, having title “Working support for laser cutting and conveyor belt comprising working support”.

Similar to the creasing module, the laser moduleis operatively connected to the PLC and provides a respective conveyor beltfor advancing the sheets to be processed.

In the apparatus according to the invention, in operation, conveyor beltis intended to continuously receive sheets exiting the creasing moduleand advance them through laser cutting station, where they will be subjected to cutting operations according to Job Controller instructions. At the exit from laser module, the sheets are almost completely processed and they can be conveyed to an appropriate stacker module.

Conventionally, the creasing moduleand the laser cutting modulehave respective encoders and respective control units or controllers in communication with the PLC.

In order for the process to be carried out optimally and with the highest precision, also in view of the fact that sheets of material pass through two or more different processing stations, suitable adhesion of the sheets to the conveyor belts must be ensured.

To this end, advantageously, all the conveyors in apparatusmay advantageously be vacuum conveyors, which, by creating a vacuum between the sheet material and the belt, avoids slippage and allows the sheet to remain held in its initial loading position, with the advantages that the following process will be performed with the highest accuracy.

In addition to the modules so far described, the apparatusfeatures an optical stationprovided upstream of the creasing module. In, the optical stationis shown applied to a connecting moduleprovided between feeder moduleand creasing module. Clearly, the depiction inshould not be understood in a limiting way, and other embodiments and arrangements of the optical stationcan be envisaged, subject to the provision of a conveyor beltintended to receive a sheet Sx to be processed and to transport it to the conveyor beltof the creasing module. Just as the other belts, advantageously conveyor beltis a vacuum belt conveyor.

The optical stationincludes at least one optical register to detect the position and the features of the sheet to be processed. The optical register can be made up of a vision system, such as a linear camera or a matrix camera, an optical scanner or optical sensors able to detect the sheet and/or the printed graphic position on it, and the like. The optical register can be designed to acquire parameters such as sheet thickness, X/Y offset positions, rotation angle and, in case, print deformation, and so on.

The optical station is operatively connected to the PLC and to the controllers of creasing moduleand of the laser cutting module, to which it transmits the acquired parameters related to the features of the loaded sheets. Such parameters are needed to determine the exact position of the sheet on which creasing and cutting will be carried out.

Advantageously, the optical stationalso features a detection system such an optical reader or scanner for detecting machine-readable media such as QR codes, barcodes and the like.

In one advantageous embodiment, the detection system is a QR code scanner apt to scan a QR code embedded in one or more of the sheets received at the optical station. The scanned code is associated with detailed workflow instructions to be performed on the sheet and it is transmitted by the optical stationto the apparatus Job Controller, which in turn can be connected to the PLC.

More specifically, the instructions can be previously stored in a job library (also referred to as “Hot folder” in the drawings) to which the Job Controller has access. The library may consist, for example, of a plurality of files, such as .pdf or scripts containing lines of instructions code with which the Job Controller can instruct the creasing and laser controllers to carry out the desired processing.

With no limitation, the QR code can be embedded in all the sheets or the in first sheet of the stackof sheets to be processed, and it can be printed together with the graphics into a scraping part of the sheet. Of course, other similar machine-readable media and scanner can be used, including both currently known systems and systems that will be developed in the future.

Apparatusaccording to the invention also includes a processing unit P operatively connected with the PLC controller and specifically configured to control and manage the entire working process of a stack of sheets. In some embodiments, the processing unit P can be integrated into the PLC controller.

In some embodiments, with laser power and the dynamic capacity of the axis motors of the creasing and laser cutting stations kept constant, the speed of the axis motors in the creasing and laser cutting modules is a function of the material thickness of the sheets S, S, . . . Sn and the length of the creasing and laser cutting profiles. The optimal working parameters of the creasing and laser cutting operations may be determined in this manner. In turn, the processing unit connected to the PLC controller then controls the speeds of the conveyor belts to optimally be synchronized, based on the parameters of the creasing and laser cutting operations.

One of the requirements for the correct functioning of the apparatus is that the feeding of the sheets takes place at an almost constant speed along all the processing stations. Since the apparatus comprises several separate modules equipped with respective conveyor belts, this implies that the conveyors must maintain essentially the same speed throughout the whole, i.e. they must be synchronized at the same speed. Advantageously, the same speed of the conveyors makes it possible that a rigid sheet exiting from one belt (e.g. of the creasing module) is directly received by the following belt (e.g. of the laser cutting module) without the need of any manual or machine transfer of the sheet. In this way the position of the sheet is always known and a portion of a long sheet of material can be laser cut in the laser module while another portion of the same sheet is creased in the creasing module.

The goal of the processing unit is precisely to control the speed of the conveyor belts in order to maintain a constant speed, for achieving the most accurate, efficient and optimal processing. Since creasing and cutting operations generally have different processing times, the processing unit, in order to keep the speed constant, is configured to adjust the parameters of the two processing stages, in particular, the speeds of the conveyor belts, by checking, inter alia, the real-time status of work.